1. Field of the Invention
The present invention relates to an optical spectrum analyzer for analyzing an optical spectrum, i.e., measuring the magnitude of signal components of the spectrum over a certain frequency range, and more particularly to an .circle.optical spectrum analyzer, the operation of which is based on an acoustooptic effect.
Various spectrum analyzers for analyzing optical spectrum are known in the art. One conventional optical spectrum analyzer that has widely been used in practice is the Czerny-Turner optical spectrum analyzer. This optical spectrum analyzer operates as follows: A diffraction grating which diffracts a light beam applied to the optical spectrum analyzer is rotated thereby to move the diffracted light over a slit. The spectrum of the light is analyzed on the basis of the angle through which the diffraction grating has been rotated when the diffracted light is detected through the slit. An optical spectrum analyzer of this type can analyze optical spectrums with high resolution.
However, Czerny-Turner optical spectrum analyzers cannot be handled with ease because they are large and heavy, and hence are not portable. Smaller and lighter optical spectrum analyzers have also been proposed, but they have a poor resolution.